Wire up the Filtered Image block end-to-end

image-filters.php

@@ -26,16 +26,39 @@ define( 'IMAGE_FILTERS_URL', plugin_dir_url( __FILE__ ) );
 /**
  * Bootstrap the plugin.
  *
- * Block registration is wired in a follow-up task. This function exists so the
- * activation hook can be added without needing a global-side-effect pattern.
+ * Registers the Filtered Image block from the build directory. The registered
+ * block type is static (its markup is produced by the JS save function).
  *
  * @return void
  */
 function image_filters_bootstrap(): void {
-    // Block registration will be added in Task 5.
+    if ( ! function_exists( 'register_block_type' ) ) {
+        return;
+    }
+
+    register_block_type(
+        IMAGE_FILTERS_DIR . 'build',
+        array(
+            'render_callback' => 'image_filters_render_block',
+        )
+    );
 }
 add_action( 'plugins_loaded', 'image_filters_bootstrap' );
 
+/**
+ * Render callback for the Filtered Image block.
+ *
+ * Static blocks render their own markup via save.js. The render_callback
+ * is a placeholder for future server-side logic (e.g. dynamic alt text).
+ *
+ * @param array  $attributes Block attributes.
+ * @param string $content    Saved block content.
+ * @return string
+ */
+function image_filters_render_block( array $attributes, string $content = '' ): string {
+    return $content;
+}
+
 /**
  * Load plugin textdomain for translations.
  *